This disclosure relates generally to transmission of data in a wireless control area network, and more particularly to a design of a transmission protocol configured to enhance communication of data from one or more sensor nodes to an access coordinator in the wireless control area network.
Patient monitoring devices are typically employed to monitor vital signs associated with a patient and present the physiological data in the form of waveforms or parameters. These patient monitors may also be configured to send audio-visual alarms when the vital signs exceed predetermined threshold values. Further, the patient monitors may be connected to a Local Area Network (LAN) to form a patient monitoring network. Also, central stations may be included in such a network setup, where the central stations may be configured to enable simultaneous review and display the physiological data collected from different patient monitors that are positioned at different locations.
More recently, with the advent of patient monitoring systems using wireless technologies, quality of patient care has been dramatically enhanced. Wireless technologies provide the freedom to communicate and exchange data, thereby enhancing the productivity and convenience of clinical workflows. For example, when a patient connected to a patient monitor is moved from a current location, such as a hospital bed, to a different location, such as an operation theater, the connection to the network may be interrupted and the patient data may be lost. Wireless networks provide an uninterrupted remote view of the patient's condition and thus enhance the quality of patient care.
Recent technological advances in integrated circuits (ICs), wireless communications, and physiological sensing allow miniature, lightweight, ultra-low power, intelligent monitoring sensor devices. A number of these sensor nodes may be integrated into a Wireless Body Area Network (WBAN), a new enabling technology for patient monitoring. The WBAN is a collection of body-worn parameter specific sensors nodes, which communicate to a body-worn access coordinator (AC) using wireless technologies, where the access coordinator may be configured to perform a wireless bridging function to communicate data from the sensor nodes to hospital infrastructure. Use of the WBAN allows the patient freedom to move around, without loss of data, thereby allowing continuous monitoring of the patient.
As will be appreciated, in a typical WBAN, the access coordinator controls the operation of the sensor nodes that exist within the WBAN. Using the currently available techniques, the access coordinator polls the sensor nodes in a round-robin fashion according to a predetermined polling sequence. Individual sensor nodes respond whenever polled by the access coordinator. In other words, the access coordinator notifies all the sensor nodes within the WBAN prior to starting a polling cycle, and the individual sensor nodes prepare data, if any, to be transmitted in response to the poll. Subsequently, the access coordinator starts polling the sensor nodes according to a predetermined polling sequence. During the data transfer period of the communication cycle, the transmission channel is occupied heavily by data bursts present in all the sensor nodes. Furthermore, data bursts from all the sensor nodes come more or less at the same time instant, disadvantageously leading to the data bursts in individual nodes to be substantially synchronized. In addition, the nature of this traffic is generally repetitive in nature. Consequently, this synchronized traffic of data poses a challenge in optimally polling the sensor nodes and efficiently handling bandwidth for data transfer, thereby resulting in data transfer delays. Moreover, the entire cycle period depends upon the time the access coordinator takes to process data and issue a command indicative of an end of communication cycle, which is again random in nature. Therefore, use of the presently available techniques results in an unpredictable amount of delay in the communication of data from the sensor nodes to the access coordinator due to the random nature of the data transfer cycle.
It may therefore be desirable to develop a design of a process that may be configured to advantageously overcome the shortcomings of the presently available techniques. More particularly, it may be desirable to enhance data transfer while minimizing data transfer delays. In addition, it may be desirable for delays associated with the sensor nodes to be as deterministic as possible.